1. Field of the Invention
Modern gasoline compositions are highly refined products. Despite this, they contain minor amounts of impurities which tend to promote corrosion during the time that the bulk fuel is being transported or maintained in storage and also during the residence time in the fuel tank, fuel lines and carburetor of a motor vehicle. A commercial motor fuel composition must contain a corrosion inhibiting additive or additive combination to inhibit or prevent corrosion during the transport and storage of the bulk fuel and during its residence time in the fuel system of the motor vehicle.
Another problem with an additive-containing motor fuel composition is the susceptibility of the additive to extraction by the aqueous caustic bottoms in storage tanks and vessels. It is essential that the inhibitor retain its effectiveness through the entire transport phase of the fuel composition and at the same time not impair the properties of the fuel composition at the point of use.
Another problem faced by fuel manufacturers is the need to comply with exhaust gas emission requirements. The pertinent regulations specify maximum emissions levels for hydrocarbons, carbon monoxide and nitrogen oxides. It is essential that any additive employed in the fuel composition for one important function, such as for corrosion inhibition, not interfere with the requirement for low exhaust gas emissions. In general, the smallest quantity of an additive employed in a gasoline for a purpose as corrosion inhibition, the less likely will complication arise due to incomplete or imperfect combustion.
2. Description of the Prior Art
U.S. Pat. Nos. 2,632,695 and 3,658,496 disclose fuel compositions in which dimer or trimer acids have been employed.
A copending application Ser. No. 887,394 filed Mar. 16, 1978, discloses a motor fuel composition containing a lactono-imidazoline reaction product.